This document explains some basic verification and debug steps for the Media Gateway Control Protocol (MGCP) on Cisco routers.

Symptoms

You can potentially encounter this list of symptoms when you configure Cisco CallManager with Cisco IOS MGCP gateways with analog Foreign Exchange Office (FXO) and Foreign Exchange Station (FXS) ports:

This configuration was tested with Cisco CallManager 3.0, 3.1, and 3.2 and various versions of Cisco IOS Software Release 12.2 images. The screen shots and Cisco IOS software configuration were captured using this software, hardware and other equipment:

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Note: Cisco IOS Software Release 12.2(11)T or later is recommended based on the ccm-manager command enhancements. The ccm-manager command requires Cisco IOS Software Release 12.1(5)XM or later on all routers (Cisco 2600 and 3600) and the Cisco Voice Gateway 200 (VG200).

The 2600 and 3600 routers support MGCP if they are running Cisco IOS Software Release 12.1(3)T or later. The release and version that you require are based on the features that you need to enable. The Cisco CallManager server must be running version 3.0(5)a or later. The router configuration is the same for all types of routers. The Cisco CallManager configuration is also the same for all types of routers.

The VG200 is supported by Cisco IOS Software Release 12.1(5)XM1 and later releases. The release and version that you require are based on the features that you need to enable. Although the VG200 is supported in earlier releases of Cisco CallManager, version 3.0(5)a or later is recommended.

These steps do not need to be performed in the order in which they appear. The show commands are useful because they display the current status of the configuration as well as verify that the changes that you made took effect.

show ccm-manager

This command verifies the active and redundant configured Cisco CallManager servers. It also indicates if the gateway is currently registered with the Cisco CallManager.

Note: This show ccm-manager command output was captured in a separated environment.

Use this command to verify the status of the router MGCP parameters. You should see the IP address of the Cisco CallManager server that you use (10.89.129.211, in this case.) All the other parameters are left at their default behavior in this configuration.

The administrative and operational state of the MGCP daemon. The administrative state controls start and stop of the application using the mgcp and mgcp block-newcalls commands. The operational state controls normal MGCP operations.

MGCP call-agent

The address of the call agent specified in the mgcp call-agent or call-agent command and the protocol initiated for this session.

MGCP block-newcalls

The state of the mgcp block-newcalls command.

MGCP send SGCP RSIP...disconnected

The setting for the mgcp sgcp restart notify and the mgcp sgcp disconnected notify commands (ENABLED or DISABLED).

MGCP quarantine mode

How the quarantine buffer is to handle Simple Gateway Control Protocol (SGCP) events.

The settings for mode, codec, and redundancy from the mgcp modem passthrough mode and mgcp modem passthrough codec commands.

MGCP TSE payload

The setting for the mgcp tse payload command.

MGCP Network (IP/AAL2) Continuity Test timer

The setting for the net-cont-test keyword in the mgcp timer command.

MGCP 'RTP stream loss' timer

The setting for the receive-rtcp keyword in the mgcp timer command.

MGCP request timeout

The setting for the mgcp request timeout command.

MGCP maximum exponential request timeout

The setting for the mgcp request timeout max command.

MGCP gateway port

The User Datagram Protocol (UDP) port specification for the gateway.

MGCP maximum waiting delay

The setting for the mgcp max-waiting-delay command.

MGCP restart delay

The setting for the mgcp restart-delay command.

MGCP vad

The setting for the mgcp vad command.

MGCP rtrcac

Whether MGCP Service Assurance Agent (SAA) Call Admission Control (CAC) has been enabled with the mgcp rtrcac command.

MGCP system resource check

Whether MGCP System Resource Check (SRC) CAC has been enabled with the mgcp src-cac command.

MGCP xpc-codec

Whether the mgcp sdp xpc-codec command has been configured to generate the X-pc-codec field for Session Description Protocol (SDP) codec negotiation in Network-based Call Signaling (NCS) and Trunking Gateway Control Protocol (TGCP).

MGCP persistent hookflash

Whether the mgcp persistent hookflash command has been configured to send persistent hookflash events to the call agent.

MGCP persistent offhook

Whether the mgcp persistent offhook command has been configured to send persistent offhook events to the call agent.

MGCP persistent onhook

Whether the mgcp persistent onhook command has been configured to send persistent onhook events to the call agent.

MGCP piggyback msg

Whether the mgcp piggyback message command has been configured to enable piggyback messaging.

MGCP endpoint offset

Whether the mgcp endpoint offset command has been configured to enable incrementing of the local portion of an endpoint name for NCS. The local portion contains the analog or digital voice port identifier.

MGCP T.38 fax low-speed redundancy: the factor set on the gateway for redundancy.

MGCP T.38 fax high-speed redundancy: the factor set on the gateway for redundancy.

show mgcp endpoint

Use this command to show the voice ports (endpoints) that are under MGCP control in the router. This command verifies which voice ports have been bound to the MGCP application. This is related to the application MGCPAPP command and the port commands that were entered under the plain old telephone service (POTS) dial peers in the document Configuring the Cisco IOS MGCP Gateway.

Use this command to display any active MGCP connections. The endpoint is Slot1/Module 0/Port 0. This corresponds to the MGCP Member Configuration identifier in Cisco CallManager. This tells you which port on the router is the endpoint in the call.

The endpoint for each call shown in the digital endpoint naming convention of slot number (S0) and digital line (DS1-0) number (1).

Call_ID(C)

The MGCP call ID sent by the call agent, the internal call control application programming interface (CCAPI) call ID for this endpoint, and the peer call legs CCAPI call ID. (CCAPI is an application programming interface [API] to provide call control facilities to applications.)

Conn_ID(I)

The connection ID generated by the gateway and sent in the acknowledgment message.

(P)ort

The ports used for this connection. The first port is the local UDP port. The second port is the remote UDP port.

(M)ode

The call mode, for which: 0—Indicates an invalid value for mode. 1—Indicates the gateway should only send packets. 2—Indicates the gateway should only receive packets. 3—Indicates the gateway can send and receive packets. 4—Indicates the gateway should neither send nor receive packets. 5—Indicates the gateway should place the circuit in loopback mode. 6—Indicates the gateway should place the circuit in test mode. 7—Indicates the gateway should use the circuit for network access for data. 8—Indicates the gateway should place the connection in network loopback mode. 9—Indicates the gateway should place the connection in network continuity test mode. 10—Indicates the gateway should place the connection in conference mode. All other values are used for internal debug purposes.

(S)tate

The call state. The values are used for internal debug purposes.

(C)odec

The codec identifier. The values are used for internal debug purposes.

(E)vent [SIFL]

Used for internal debug purposes.

(R)esult [EA]

Used for internal debug purposes.

show voice port mod_number/slot_number/port_number

Use this command to verify the current status and configuration of the voice ports on the router.

This is sample output from the show voice port command for an FXO voice port:

psy-voice-01#show voice port 1/1/0
Foreign Exchange Office 1/1/0 Slot is 1, Sub-unit is 1, Port is 0
Type of VoicePort is FXO
Operation State is DORMANT
Administrative State is UP
No Interface Down Failure
Description is not set
Noise Regeneration is enabled
Non Linear Processing is enabled
Non Linear Mute is disabled
Non Linear Threshold is -21 dB
Music On Hold Threshold is Set to -38 dBm
In Gain is Set to 0 dB
Out Attenuation is Set to 3 dB
Echo Cancellation is enabled
Echo Cancellation NLP mute is disabled
Echo Cancellation NLP threshold is -21 dB
Echo Cancel Coverage is set to 8 ms
Playout-delay Mode is set to adaptive
Playout-delay Nominal is set to 60 ms
Playout-delay Maximum is set to 200 ms
Playout-delay Minimum mode is set to default, value 40 ms
Playout-delay Fax is set to 300 ms
Connection Mode is normal
Connection Number is not set
Initial Time Out is set to 10 s
Interdigit Time Out is set to 10 s
Call Disconnect Time Out is set to 60 s
Ringing Time Out is set to 180 s
Wait Release Time Out is set to 30 s
Companding Type is u-law
Region Tone is set for US
Analog Info Follows:
Currently processing none
Maintenance Mode Set to None (not in mtc mode)
Number of signaling protocol errors are 0
Impedance is set to 600r Ohm
Station name None, Station number None
Translation profile (Incoming):
Translation profile (Outgoing):
Voice card specific Info Follows:
Signal Type is loopStart
Battery-Reversal is enabled
Number Of Rings is set to 1
Supervisory Disconnect is signal
Answer Supervision is inactive
Hook Status is On Hook
Ring Detect Status is inactive
Ring Ground Status is inactive
Tip Ground Status is inactive
Dial Out Type is dtmf
Digit Duration Timing is set to 100 ms
InterDigit Duration Timing is set to 100 ms
Pulse Rate Timing is set to 10 pulses/second
InterDigit Pulse Duration Timing is set to 750 ms
Percent Break of Pulse is 60 percent
GuardOut timer is 2000 ms

Note: FXO ports in loopstart mode normally disconnect calls when they detect a second battery reversal (back to normal). Use the no battery-reversal command on FXO ports to disable this action. If an FXO port or its peer FXS port does not support battery reversal, avoid configuring battery-reversal or battery-reversal answer on the FXO port. On FXO ports that do not support battery reversal, the battery-reversal command can cause unpredictable behavior, while the battery-reversal answer command prevents calls from being answered. Use the no battery-reversal command to ensure that battery reversal answer is disabled on FXO ports that do not support battery reversal.

Note: This example disables battery reversal on voice port 1/1/0 on a router.

voice-port 1/1/0
no battery-reversal

This is sample output from the show voice port command for an FXS voice port:

psy-voice-01#show voice port 1/0/0
Foreign Exchange Station 1/0/0 Slot is 1, Sub-unit is 0, Port is 0
Type of VoicePort is FXS
Operation State is UP
Administrative State is UP
No Interface Down Failure
Description is not set
Noise Regeneration is enabled
Non Linear Processing is enabled
Non Linear Mute is disabled
Non Linear Threshold is -21 dB
Music On Hold Threshold is Set to -38 dBm
In Gain is Set to 0 dB
Out Attenuation is Set to 3 dB
Echo Cancellation is enabled
Echo Cancellation NLP mute is disabled
Echo Cancellation NLP threshold is -21 dB
Echo Cancel Coverage is set to 8 ms
Playout-delay Mode is set to adaptive
Playout-delay Nominal is set to 60 ms
Playout-delay Maximum is set to 200 ms
Playout-delay Minimum mode is set to default, value 40 ms
Playout-delay Fax is set to 300 ms
Connection Mode is normal
Connection Number is not set
Initial Time Out is set to 10 s
Interdigit Time Out is set to 10 s
Call Disconnect Time Out is set to 60 s
Ringing Time Out is set to 180 s
Wait Release Time Out is set to 30 s
Companding Type is u-law
Region Tone is set for US
Analog Info Follows:
Currently processing unknown
Maintenance Mode Set to None (not in mtc mode)
Number of signaling protocol errors are 0
Impedance is set to 600r Ohm
Station name None, Station number None
Translation profile (Incoming):
Translation profile (Outgoing):
Voice card specific Info Follows:
Signal Type is loopStart
Ring Frequency is 25 Hz
Hook Status is Off Hook
Ring Active Status is inactive
Ring Ground Status is inactive
Tip Ground Status is inactive
Digit Duration Timing is set to 100 ms
InterDigit Duration Timing is set to 100 ms
No disconnect acknowledge
Ring Cadence is defined by CPTone Selection
Ring Cadence are [20 40] * 100 msec
Ringer Equivalence Number is set to 1

Explanation of Fields in show voice port Command Output

Administrative State

Administrative state of the voice port.

Alias

User-supplied alias for this voice port.

Clear Wait Duration Timing

Time of inactive seizure signal to declare call cleared.

Connection Mode

Connection mode of the interface.

Connection Number

Full E.164 (ITU-T) telephone number used to establish a connection with the trunk or private line, automatic ringdown (PLAR) mode.

Currently processing

Type of call currently being processed: none, voice, or fax.

Delay Duration Timing

Maximum delay signal duration for delay dial signaling.

Delay Start Timing

Timing of generation of delayed start signal from detection of incoming seizure.

Dial Type

Out-dialing type of the voice port.

Digit Duration Timing

Dual tone multifrequency (DTMF) digit duration in milliseconds.

E&M Type

Type of ear and mouth (E&M) interface.

Echo Cancel Coverage

Echo cancel coverage for this port.

Echo Cancellation

Whether echo cancellation is enabled for this port.

Hook Flash Duration Timing

Maximum length of hook flash signal.

Hook Status

Hook status of the FXO/FXS interface.

Impedance

Configured terminating impedance for the E&M interface.

In Gain

Amount of gain inserted at the receiver side of the interface.

In Seizure

Incoming seizure state of the E&M interface.

Initial Time Out

Amount of time the system waits for an initial input digit from the caller.

InterDigit Duration Timing

DTMF interdigit duration in milliseconds.

InterDigit Pulse Duration Timing

Pulse dialing interdigit timing in milliseconds.

Interdigit Time Out

Amount of time the system waits for a subsequent input digit from the caller.

Maintenance Mode

Maintenance mode of the voice port.

Music On Hold Threshold

Configured Music On Hold threshold value for this interface.

Noise Regeneration

Whether background noise should be played to fill silent gaps if voice activity detection (VAD) is activated.

Number of signaling protocol errors

Number of signaling protocol errors.

Non Linear Processing

Whether nonlinear processing is enabled for this port.

Operation State

Operation state of the port.

Operation Type

Operation of the E&M signal: two-wire or four-wire.

Out Attenuation

Amount of attenuation inserted at the transmit side of the interface.

Out Seizure

Outgoing seizure state of the E&M interface.

Port

Port number for this interface associated with the voice interface card.

Pulse Rate Timing

Pulse dialing rate in pulses per second.

Region Tone

Configured regional tone for this interface.

Ring Active Status

Ring active indication.

Ring Frequency

Configured ring frequency for this interface.

Ring Ground Status

Ring ground indication.

Signal Type

Type of signaling for a voice port: loop-start, ground-start, wink-start, immediate, or delay-dial.

Slot

Slot used in the voice interface card for this port.

Sub-unit

Subunit used in the voice interface card for this port.

Tip Ground Status

Tip ground indication.

Type of VoicePort

Type of voice port: FXO, FXS, or E&M.

The Interface Down Failure Cause

Text string that describes why the interface is down.

Wink Duration Timing

Maximum wink duration for wink start signaling.

Wink Wait Duration Timing

Maximum wink wait duration for wink start signaling.

show mgcp statistics

Use this command to show statistical information related to MGCP activity on the router.

The number of Create Connection messages received from the call agent by the media gateway. Messages received are classified as successful or failed.

DeleteConn rx

The number of Delete Connection messages received from the call agent by the media gateway. Messages received are classified as successful or failed.

ModifyConn rx

The number of Modify Connection messages received from the call agent by the media gateway. Messages received are classified as successful or failed.

DeleteConn tx

The number of Delete Connection messages sent by the call agent. Messages received are classified as successful or failed.

NotifyRequest rx

The number of Notify messages received by the call agent from the media gateway. Messages received are classified as successful or failed.

AuditConnection rx

The number of Audit Connection messages received from the call agent by the media gateway. Messages received are classified as successful or failed.

AuditEndpoint rx

The number of Audit Endpoint messages received from the call agent by the media gateway. Messages received are classified as successful or failed.

RestartInProgress tx

The number of Restart In Progress (RSIP) messages transmitted by the call agent. Messages received are classified as successful or failed.

Notify tx

The number of Notify messages transmitted by the call agent. Messages received are classified as successful or failed.

ACK tx

The number of acknowledgment messages transmitted by the call agent.

NACK tx

The number of negative acknowledgment messages transmitted by the call agent.

ACK rx

The number of acknowledgment messages received by the gateway.

NACK rx

The number of negative acknowledgment messages received by the gateway.

IP address

The IP address of the call agent.

Total msg rx

The total number of messages received by the gateway. Messages received are classified as successful or failed.

debug mgcp [all | errors | events | packets | parser]

Use these commands when you experience problems that you believe are not related to configuration errors or hardware problems. Keep an example of each debug command from a working configuration to use for comparison when you experience problems.

In some instances it might be necessary to shut down and then reenable the voice ports on the MGCP gateway. If calls cannot be made over FXO ports, there is no dial tone on FXS ports, or you experience similar problems, try this step:

psy-voice-01(config)#voice-port 1/0/0
psy-voice-0(config-voiceport)#shutdown
Both ports are out of service
psy-voice-0(config-voiceport)#
00:25:44: %LINK-3-UPDOWN: Interface Foreign Exchange Station 1/0/1, changed
state to Administrative Shutdown
00:25:45: %LINK-3-UPDOWN: Interface Foreign Exchange Station 1/0/0, changed
state to Administrative Shutdown
psy-voice-0(config-voiceport)#no shutdown
Both ports are in service
psy-voice-0(config-voiceport)#
00:26:03: %LINK-3-UPDOWN: Interface Foreign Exchange Station 1/0/0,
changed state to up
00:26:03: %LINK-3-UPDOWN: Interface Foreign Exchange Station 1/0/1,
changed state

Note: This step is known to resolve several different issues related to problems with FXS and FXO ports.

This happens when Cisco CallManager sends out an ISDN NOTIFY to the Telco and the Telco side does not support it. After NOTIFY is received three times, the Telco might drop the call. In order to suppress these notify messages to the PSTN, complete these steps.

Choose Service>Service Parameters, select the Publisher server IP address and choose the service as CallManager.

Click Advanced in the Service Parameter page and search for the heading Clusterwide Parameters (Device - PRI and MGCP Gateway).

Set the Enable DMS PRI Notify Message from User to Network parameter value to False and click on Update.